Industrial stoker



April 9, 1929. c. F. MILLER 1,708,393

INDUSTRIAL STOKER Filed Dec. 21, 1923 4 Sheets-$heet III Chas. F: Miller INVENTOR ATTORN EY April 9, 1929. c. F. MILLER INDUSTRIAL STOKER Filed Dec. 21, 1923 4 Sheets-Sheet all I C/ma. [Nil/er INVENTOR ATTORNEY WITNES i074 April'9, 1929. c. F. MILLER 1,708,393

INDUSTRIAL STOKER Filed Dec. 21, 1925 4 Sheets-Sheet 5 INVENTOR ATTORNEY A ril 9,1929. c. F. MILLER INDUSTRIAL STOKER Filed Dec. 21, 1923 4 Sheets-Sheet Chas; E Miller INVENTOR WITNESSES:

ATTORNEY Patented Apr. 9, 1929.

UNITEDSTATES PATENT OFFICE.

CHARLES F. MILLER, 01: MOORE, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELEC- TRIC AND MANUFACTURING COMPANY, A CORIPORATION OF PENNSYLVANIA.

INDUSTRIAL STOKER.

Application filed December 21, 1923. Serial No. 682,131.

My invention relates to industrial stokers of the type wherein fuel is introduced through a main retort extending from the front toward the back of the stoker and spreads out from said retort over one or more sloping grate surfaces extending from the margin or margins thereof, and it has for its object to provide apparatus of the character designated which shall'be effective to burn fuels of varying character and grades efiiciently and without clogging.

A further object of my invention is to provide a dumping mechanism for a stoker of the character above described which shall serve to dump the refuse at will while, at the same time, preventing avalanching of the fuel bed.

In the accompanying drawing, Fig. l is a fragmentary plan view of a stoker constructed in accordance with my invention; Fig. 2 is a sectional View of the structure shown in Fig. 1 taken along the plane II-II in Fig. 1; Fig. 3 is a side view of a tuyere bank, together with associated operating mechanism as may be employed in the structure of Fig. 1, the view being taken on some such plane as that indicated at IIIIII in Fig. 1; Fig. 4 is a detail view of a mechanical movement employed in the structure of Fig. 1 to translate the reciprocatory movement of the main ram drive to oscillating movement of a shaft suitable for actuation of grate members as will hereinafter more fully appear; Fig. 5 is a side view of'the structure shown in Fig. 1, being taken along'the plane indicated at V-V; Fig. 6 is a detail View of the dump grate mounting; Fig. 7 is a plan View of the same; and Fig. 8 is a detailed view showing a modified form of tuyere bank operating mechanism similar to that shown in Fig. 3.

In the operation of so-called industrial boilers as are employed for the heating of public buildings and in small manufacturing plants, it is desirable to employ a mechanical stoker of relatively small capacity as compared with the so-called multi-retort underfeed stoker and which shall furthermore require much less height of fire box than is necessary for the multi-retort underfced stoker.

lVith these and other objects in view, I provide. a stoker in which a main retort extends rearwardly from the front wall in a substantially horizontal direction but little above-the floor of the fire box, and I force fuel thereinto from a hopper of the usual type by means of a main ram and, if desired, by auxiliary rams disposed within the retort.

Said retort has substantially continuous sides, and sloping away from one or both of the margins thereof I provide a grate surface, the inclination being such as to promote lateral movement of the fuel from the retort without avalanching thereof. grate surface is preferably formed of tuyerc banks alternating with moving fuel rams, hereinafter designated as lateral rams, said rams and tuyeres lying in substantially the same plane. If desired, the tuyere banks themselves may also be capable of movement. At the foot of the grate surface or surfaces thus provided, I may provide a dump plate normally occupying a substantially horizontal position, but susceptible of bodily motion toward the grate, while at the same time elevating the edge thereof adjacent to the grate, whereby refuse supported thereupon is dumped away from the grate and at the same time, said up-raised edge effectively prevents the avalanching of the fuel bed.

Referring to the drawing for amore detailed understanding of my invention, I show the front wall of a fire box at 10 in Figs. 1 and 5. Disposed in front of this wall is a hopper 11 of usual form discharging into a ram box 12.

A steam cylinder 13 is provided in front of the hopper 11 and a piston therein contained is directly connected with a main fuel ram 14 and, if desired, auxiliary fuel rams 15 and 16 within the fire box may also be driven directly from the steam cylinder 13 as through a rod 17. 1

The specific nature of the steam operating mechanism 13 forms no part of the present invention, but a preferred form is illus trated and claimed in my co-pending application Serial No. 663,436, filed Sept. 18, 1923, Patent Number 1,624,004 and assigned to the Vestinghouse Electric and Manufacturing Company. Suffice to say, by means of suitable valve mechanism 18, the steam cylinder 13 may be caused to operate the main fuel ram at any desired speed within the range of capacity of the stoker in question.

Projecting inwardly from the ram box 12 This is a main retort 19 extending to the back of the stoker as indicated at I having its' bottom substantially horizontal throughout its length except for an upward inclination of the bottom at the rear as indicated at 21.

supported relatively close to the floor of the fire box, as by suitable supports 2222.

' retort is forced As indicated in Fig. 2, the side of the main retort 19 is formed by a plate 2323 surmounted by castings 24L alternating with castings 2.5, the respective arrangement of these latter castings being more clearly shown in Fig. 5. It will be noted that the upper edge of the side wall thus formed is an approximately continuous unbroken line so. that all fuelv introduced into the main to ascend up over said side wall before reaching other parts of the stoker. I r

Sloping away from the retort margin thus formed is a grate surface embodying tuyere banks 26-26 with intervening lateral fuel rams 2727, these elements coacting topro- .vide an approximately flat grate surface inasmuch as the upper surfaces of the rams Pas by a link and bevel gear connection indicated in Fig. 4. This specificv connection forms no' part of the present invention but is separately described and claimed in my co-pending application Serial No. 631,661, filed April 12, 1923, Patent No. 1,657,224 and assigned to the Westinghouse Electric and Manufacturing Company. Suffice to say, a connection 30 on the main ram swings a link 31 provided with an arcuate slot 32, thefurther end 33'of the link 31 being pivoted on a crank arm34 movable about a fixed center 35. A crank arm 36 is also movable about the center 35 and is connected on. the one hand through a link 37 to a pin 38 in the slot 32, and is connected, on the other hand, toa portion of a beveled gear 39 meshing with a similar portion of a beveled gear 40' mounted upon the end of the shaft 29. Thus, by reciprocation of the member 30, the are member 31 swings and moves laterally in space, oscillating the bevel gear 39 through the link 37 with consequent oscillation of the shaft-29. A screw 7 O determines the location of the pin 38 in the slot 32, moving said pin toward the floating pivot 33 shortening the degree of oscillation 20 and preferably chanical movement may The main retort structure is of the shaft 29 with a givenmotionof the main ram and vice versa.

Obviously any other suitable form ofnietranslating said reciprocating driving motion into said oscillatory driven motion.

lVhere the shaft 29 passes beneath the V lateral rams 27, itis provided with a gear portion ll meshing with a rack member 42 pivot-ally connected to therespective upper rams 27 and also connected through a link 43 with the lower rams 27.. Thus, by oscillation of the shaft 29,'the rams 27-27 are given a to-and-fr-o motion on their curved seats, the result of the specific arrangement thus described being that the motion of said rams is a combination of reciprocation and tilting, inasmuch as at the upper limit of motion, the upper ends of the rams are thrown up, and at the lower, limit of travel the lower ed es are thrown up. By virtue of this specificmotion, not only is the fuel fed downwardly over the grate surface, but also is raised'and lowered, breaking up the partially fused mass to enable the air to pass freely therethrough and also serving to free the tuyere openings in theram lllQllb' bers 27- 27 so as to permit the ready escape ofair therefrom.

This l'ast nained function of the rams 2727 is of considerable importance, these rams being formed of tuyere members 4 1- 44 with air. openings l5. at the lower edges thereof so as to permit the free flow of air thereinto. 7

WVith certain types of fuel; and conditions of the fuel bed, the structure thus described to this point functions satisfactorily with the vtuyere banks 262 6 fixed in position. I find, however, that with certain types of fuel, more particularly those types wherein be employed "for cooking tends to provide strongly cohesive rams are ineffectual. Toobviate this action,

I may arrange thetuyere banks 26+26 for reciprocation asindicated in Fig. 3. The respective tuyeres are mounted on a plate 46 so arranged. that air may pass readily therethrough, and this plate is provided with a depending arm or lug 47 extending down to a plane below thatrof the shaft 29. The arm 47 is provided with apivotal opening 48 disposed above the shaft 29 and with a similar pivotal opening 49 disposed below the shaft 29. I A'erankarm 50 is clamped upon the shaft '29 and is connected to the pivotal point 4-9 as by a link 51; Thus, the oscillatory motion of the shaft 29 causes reciprocation of the tuyere bank 26 upon supports 52 and 53. r

It will be noted that inasmuch as the lateral rarns 27-27 are driven from the upper side of the shaft 29, whereas the tuyeres 26 are driven from the lower side of the shaft 29, there is a marked difference in phase between the motions of the two elements, that is to say, the tuyeres 26 are moving upwardly while the lateral rams 27-27 are moving downwardly and vice versa, thus providing a very effectual movement of the fuel bed under all conditions.

If it be desired that the fuel bed be not agitated as yiolent-ly as is the case with this construction, the crank'arm 50 may be unclamped from the shaft 29 and swung to such a position that the crank arms projects above said shaft, as shown in Fig. 8. The link 51 is then connected in the pivotal opening 48 and, under these conditions, the movement of the tuyeres 2626 is substantially in phase with the movement of the lateral rams 2727, although the range of movement is, in general, not the. same, so that there is still a slight shearing action tending to keep the fuel bed in a broken-up condition.

By adjustment of the screw 70, the stroke of the lateral rams and of the tuyeres may be altered with a fixed stroke of the main 'am, thus hastening or slowing up the rate of fuel travel over the lateral grate to accord with the rate of fuel introduction by the main ram and to modify the shape of the fuel bed.

Disposed at the lower edge of the inclined grate surface is a dump plate 55 made up of suitable plate elements, and this dump plate is carried on a .transversely-extending shaft 56 supported at its ends in suitable rollers, one of which is shown at 57 in Figs. 6 and '7. Each of these rollers is carried on a track member 5859, preferably encased within the furnace wall so as to shield the roller from heat and also to protect it from dust and dirt.

A dumping shaft 60 extends transversely of the lateral grate beneath the lower edge thereof and may be oscillated as through a handle 61. Links 62 are attached to the shaft 56 on the one hand, and to the ends of crank arms 63 mounted on the shaft 60 on the other hand, so that oscillation of the shaft 60 tends to cause bodily translation of the entire dump plate structure to and from the sloping grate, this movement being permitted by movement of the rollers 57 on the tracks 5859.

Additional crank arms 64 are also carried by the shaft 60 and engage the dump plate 55 near the ed e thereof adjacent to the.

lower edge of the grate surface. Thus, in the position shown in full lines in Fig. 2, the dump plate is substantially in the normal position, closing the dumping opening and adapted for the reception of refuse. Movement of the handle 61 in a clockwise direction tends to move the dump plate toward the grate but, at the same time, the arms 64 throw up the right-hand edge of the dump plate 55 so that it clears the lower edge of the grate and in the dumping position, indicated roughly in dotted lines at 65, it will be noted that this upturned edge projects suiliciently above the lower et of the grate to prevent avalanching of the fuel.

As is common with stokers of this type, air under pressure may be supplied bei oath the entire grate surface, this air passing through the tuyere opening in the tuyere bank 26 and also through the openings in the lateral rams and through suitable side wall tuyeres, if desired, whereby effectiveness and flex'ibility of operation may be secured.

From all the foregoing, the operation of the device will be obvious. Coal is fed into the hopper ll, forced into the main retort by the rams l4, l5 and 16 and is there largely coked. The resultant mass rises up out of the main retort, pouring over the retort margin down upon the lateral grate where it is supplied with an abundant amount of air to insure complete combustion, a uniform progressive movement being imparted thereto by the reciprocation of the tuyercs 2G and of the lateral rams 27. The refuse accumulating upon the dump plate may be discharged at will by the operator without material disturbance of the fuel bed, because of the advantageous damming action of the rip-raised action. of the dump plate during the dumping operation.

f greater capacity is desired, a similar inclined grate surface may be provided sloping away from the other margin of the main retort.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed there upon as are imposed by the prior art or as are specifically set forth in the appended claims.

That I claim is 1. In a mechanical S LO-l'OI tion with a longitudinally tending retort having means for introdu ing fuel thereinto, of an overfeed grate surface extending laterally and downwardly from an upper margin of the retort and comprising alternately ai anged tuyere banks and fuel feeding means, said fuel feeding mea inclut ing curved seats extending laterally with respect to the retort and rams mounted to reciprocate therein, and mechanism for moving said rams upon said seats laterally with respect to the retort.

2. In a mechanical stoker, the combination with a longitudinally extending retort having means for introducing fuel thereinto, of an overfeed grate surface extending latthe combinaarranged erally and downwardly from an upper margin of the retort and comprising alternately tuyere banks and fuel feeding means, each of the fuel feeding means including a concave supporting surface'extending laterally with respectto the retort and a ram slidably mounted on said concave supporting surface, and mechanism "for moving said rams laterally with respect to said retort whereby acombincd reciprocatory and tilting motion is imparted to each 3. In a mechanical stoker, the combination with a longitudinally extending-retort having means for introducing 'luel thereinto, of

an overfeed gratesurface extending laterally and downwardly'from an upper marretort and arranged in end to end relation and a ram slid-ably mounted on each of the concave supporting surfaces, and mechanism for moving the rains laterally with respectto said retort.

In testimony whereof, I have hereunto subscribed my name this 20th day of Decemher, 1923. a v

CHARLES F. MILLER 

